What the FDA labels say about taking them together
Medroxyprogesterone and tamoxifen
Tamoxifen's FDA label of December 18, 2025 names medroxyprogesterone in its drug interactions section; the medroxyprogesterone labels PlainMeds reads (3) do not name tamoxifen. The tamoxifen label: “Medroxyprogesterone reduces plasma concentrations of N-desmethyl, but not tamoxifen.”
Check it at the source: the medroxyprogesterone FDA label on DailyMed (effective June 29, 2026, Pharmacia & Upjohn Company LLC); the tamoxifen FDA label on DailyMed (effective December 18, 2025, Actavis Pharma, Inc.).
What does the medroxyprogesterone label say about tamoxifen?
Medroxyprogesterone's label (effective June 29, 2026) and its 2 other brand-application labels do not name tamoxifen in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Provera), NDA011839 (Pfizer), as published by Pharmacia & Upjohn Company LLC, effective June 29, 2026 (SPL set a586be28-96af-4fed-a13f-9b94fd4c7405), via openFDA; the full label on DailyMed
What does the tamoxifen label say about medroxyprogesterone?
Tamoxifen label, drug interactionsMedroxyprogesterone reduces plasma concentrations of N-desmethyl, but not tamoxifen.
Source: FDA drug label (Tamoxifen Citrate), Actavis Pharma, Inc., effective December 18, 2025 (SPL set 9b8a4211-120f-4981-ad69-928accb97637), via openFDA; the full label on DailyMed
These are the labels' own sentences. PlainMeds does not grade interactions; a pharmacist or prescriber can say what they mean for one person's medicines.
Both medicines on the record
| Medroxyprogesterone | Tamoxifen | |
|---|---|---|
| Labeled for | Birth control, Pain | Breast cancer |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | $22.85 per mL 150 mg/mL | $0.277 per tablet 20 mg tablet |
| Shortage now | A presentation being discontinued | No current entry |
Source: FDA NDC Directory, CMS NADAC of October 7, 2026 and the FDA Drug Shortage Database (FDA files October 8, 2026)
What next?
- Check more medicines together
- up to five at once